Detroit Diesel 4000 Series, Service Manual, Page: 2639 / 2706

SERIES 4000 12/16V SERVICE MANUAL
Ensure tight connections, good grounding points, and no bad wires. Check all electrical
connectors to ensure none are broken, cracked, or damaged. Go to step 5 for a further
probable cause.
5. Solenoid valve may not be working properly.
Check for proper operation. Install a pressure gage in the "COM" or "CLUTCH" port.
If the pressure gage readings are correct, bypass the solenoid valve to check fan clutch
lockup. Remove the oil supply hose from the "NO" or "INLET" port on the solenoid
valve, and reattach it directly to the "CONTROL PRESSURE" port in the fan clutch.
Install a pressure gage in the line as close to the fan clutch as possible. Cap or plug all
open connections.
To avoid injury when working near or on an operating
engine equipped with a hydraulic clutch fan:
3
Never work in close proximity to the fan.
3
Never try to keep the fan from rotating by holding the
fan.
3
Never tie down the fan with straps, chains, or other
restraints.
3
Never shut off the oil supply to the fan clutch.
To avoid injury when working near or on an operating
engine equipped with a hydraulic clutch fan, remove loose
items of clothing and jewelry; tie back or contain long hair
that could be caught in any moving part causing injury. A
hydraulic fan may start without warning.
Start the engine. The fan clutch should be locked up, when a minimum of 40 psi. engine oil
pressure is provided. (The clutch must be supplied with a minimum of 40 psi oil pressure
applied to the "CONTROL PRESSURE" port.) Go to step 6 for a further probable cause.
6. Clutch plates worn out.
If breakaway torque is below specifications, repair or replace the fan clutch;
refer to section C 221.05.05C 221.05.05 .
All information subject to change without notice.
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